<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        html,body{
            width: 100%;
            height:100%;
            margin: 0px;
            padding: 0px;
            overflow: hidden;
        }
    </style>
</head>
<body>
    <div style="width: 100%; height:100%; text-align: center; font-size: 6rem; padding-top: 10rem;">
        欢迎使用
    </div>
</body>
</html>